How To Ruin A Perfectly Good Lamp With A Nexus 7

Hi Friends!

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I hope you’ve all had the opportunity to enjoy your favorite food recently. (I tried to come up with an alternative friendly greeting. I think I nailed it.) This post could alternatively be called “What To Do With Your Nexus 7, When You Crack The Screen”, but, I’m weird.

ANYWAY! (As most of these posts start off) I was browsing eBay a couple months ago for a secondhand Nexus 7, and I learned some things.

  • Once you crack the screen on a Nexus 7, the digitizer will completely stop functioning. (In most cases, but perhaps not all… N7 users can chime in here?)
  • Replacement digitizers are really expensive. ($60+, and I saw as much as $160+ for some.)
  • Due to these facts, people were selling their tablets at what could only be described as “mega-balls cheap”.

Most of my queries turned up an average unit price for an 8GB cracked screen N7 of $50. I managed to snag one at $45 shipped, which is a fantastic price for the specs this tablet carries. Just now, the lowest price I could find was $60. There’s some amount of luck involved. Just to quickly recap the N7s specs:

  • Quad-Core Tegra 3
  • 1GB of RAM
  • ~8GB of Storage
  • Wifi + Bluetooth
  • USB Host/USB OTG
  • Built-In Battery, Charger
  • Audio Out
  • Unlockable Bootloader

So, basically… features that you’d pay a sizable amount more for an equivalent ARM SBC. And, the icing on the cake is that this will run: Ubuntu 13.04, Android 4.2.2, and Ubuntu Touch. I’m sure there’s more that I’m leaving out, but for all my intents and purposes these will do just fine. Out of the box Android 4.2.2 will allow you to use a keyboard and mouse with your N7, provided you have a USB-OTG cable.

I’m sure if you’re trying this out, you’ve realized the problem. In order to efficiently use your N7 with an external keyboard and mouse, you need to prop it up on something. If you’re using it in your lap, it’s falling over a lot, and you’re probably wanting to crack the screen more out of spite. DON’T DO IT, FRIENDO.

Instead, this cute $20 lamp can help you create a new friendly desk (immobile) robot. You’ll be the TALK OF THE TOWN, let me tell you.

Hardware Disclaimer:
If you ruin your Mom’s favorite lamp with this hack, you’ll be in big trouble. Don’t do anything silly. If you drill holes in your $1,000,000 Persian Rug, I cannot help you. I take no responsibility for your actions if you’re following this tutorial, and CERTAINLY NOT IF YOU’RE NOT FOLLOWING IT, since I spent all this time writing these instructions, for you to just IGNORE ME, GAH!

Parts:
Hampton Bay Architech Lamp (Matte Black) – $20
Nexus 7 – Cracked Screen – ~$40 – $60
Dremel with Metal Cutting Discs
Wire Cutters
USB A->B 6FT
USB OTG Cable
Soldering Iron
USB Hub
Philips Screwdriver
Needlenose Pliers
Flat-Head Bolts+Nuts+Crush washers
5V Supply (or hopefully, the Nexus 7 Charger)
Drill+Bits

Steps:

1. Unbox poor defenseless Lamp. Attach to base. Promptly break out your Dremel and metal cutting discs, saw off the two rivets that connect the lamphead to the springy-body. Be careful to leave the silver bracket intact, as you’ll be using that for the N7. Once the head is loose, you have to take pieces of the body apart to remove the AC cable. You might be able to get away with chopping it up, and tugging on the cable until it comes free… But, to save yourself some busted knuckles, I suggest you do it the slow way.
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2. Your lamp will now refuse to do anything but spring completely upright, as there’s no weight to counterbalance the springs. Measure out where you’d like to mount your N7. I measured to what is roughly the center of my tablet, and made marks on the backplate that correspond to the holes on the silver bracket of the lamp body. Remove your backplate, (You should be able to stick something along the seam and pry it off, it snaps right off, no screws.) and drill the holes. The holes should be the about size of the flat-head bolts you selected. The washers will make up the play, so don’t sweat it if they’re a little loose. Also, don’t drill through the NFC coil, or any of the antennas. That’s important.

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3. Thread the washers onto the bolts, and the bolts through the silver lamp-body bracket. Put the bolts through the holes you drilled in your backplate, and secure the backplate with the nuts. Tighten them fully. Use your Dremel to grind off excess bolt, as that’ll press against your N7’s battery/motherboard if left there. Clean dust thoroughly, then apply a dab of hot glue on one of the nut faces, against the backplate. Cover the nuts with electrical tape, (Hahahahahahahaha… Sorry, sorry.) so they don’t short anything out.

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4. It should look something like the above. ^ Now, snap in your Nexus 7! Congratulations, you’ve made yourself a cute little Pixar-lamp-buddy.

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Software Disclaimer: Look, I hate writing these, but if you brick your device, you’re on your own. These instructions are in no way all-encompassing, or perfect. There is a lot of assumed knowledge. If you need some advice, email me. I’m always happy to help.

Now, you’re at a crossroad. There’s a lot of software routes to take, and I’ll in no way cover them all. I’m sure you’ll also wondering why I listed all of that USB cable stuff in the Parts section. Let’s start with Android, since that’ll be the default. If you fancy it, you can follow the steps here to flash CyanogenMod, unlock your bootloader and root your tablet. I will not cover CyanogenMod steps, which differ (slightly different kernels), but the general concepts will apply.

The conundrum about this setup is that it’s currently impossible to use a keyboard/mouse and charge your tablet at the same time. The N7 will boost it’s battery power to the USB OTG port while it’s in host mode, which means it cannot be accepting current for the charger. This awesome person named Timur created a kernel for the stock Android 4.2.2 setup that will allow you to charge and host devices at the same time. You can find it here. You want the one for “Fixed Installation”.

You’ll need to unlock your device’s bootloader before you can flash the USB+Charging Kernel. For this, you’ll need fastboot. Here are the instructions for unlocking your device’s bootloader, courtesy of Ubuntu. For Mac and Linux, here is a page that hosts the fastboot binary – you can find it in the zip for your respective OS. You don’t have to run that silly shell script if you don’t want to “install” the binary, you can just invoke it directly.  If using Linux, you may also find it in your respective package repository, which is a better option.

Unpack Timur’s USB+Charging Kernel for Android 4.2.2 ZIP (Make sure you are running 4.2.2….), and grab the boot.img file. Boot your tablet into fastboot mode (following instructions on Ubuntu’s Wiki.), and connect the microusb cable to your Linux/OS X machine.
Now, issue the following command (this assumes that fastboot is in the PATH and the boot.img is in the current directory):

fastboot erase boot && fastboot flash boot ./boot.img

Once fastboot reports success, you can reboot your tablet. It should boot up just fine, and look exactly as before, but now, if you go into your About Tablet menu, your kernel version will be “3.1.10-gdb06546-dirty Timur-USBhost-FI-2013-01-29@hexa #27”. Success!

If your tablet goes into a boot loop, or doesn’t boot at all… Don’t panic. (42) Google has the stock Android images and instructions on how to flash them, here. “Fastboot mode” can always save you if you nuke your device, but… just be careful. And, don’t EVER pull power on your device while a flash is in progress. I should also warn you, flashing kernels/ROMs from the Internet carries some risk, as you can never be fully sure what changes were made. (Unless you diff the source yourself… Good luck with that.) But, I’ve tested Timur’s kernel, and it works as expected.

Timur’s explanation page shows you how to wire your N7 so that you can use the hub and charge it at the same time (with the modified kernel.) It also goes into some more detail about what is meant by “Fixed Installation”. The wiring diagrams are in the “Using An USB Hub” section. I’ve noticed that there are times when I’ll need to replug the USB OTG connector to get the hub to recognize the connected devices again. It’s somewhat fragile, but generally, it works as it should.
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Wrap-Up:

My N7 runs Spotify/Clock duties at my desk, and thanks to the lamp arm, can be positioned right above my screens. The lamp arm also swivels, so you can use it in portrait and landscape mode! The USB subsystem will occasionally be confused when returning from sleep, which will require a replug. In your Settings, under Developer Options, there’s an option called “Stay Awake”, in which the screen will not sleep while the system is charging. Be sure to enable “Day Dreaming” aka “Android Screensaver’ though, to prevent any chance of burn-in. That’s about it! It’s a great little machine for extra-desk stuff. The sky’s the limit in terms of apps, THE WORLD IS YOUR OYSTER! (This is also awesome for video chats. Just saying.)

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